In a known sensor a camera is used to detect a barcode on a substrate. The camera repeatedly forms still images of the substrate and transmits these images to the code analyser. The code analyser performs image processing algorithms to determine the code, e.g., a number associated with the barcode, from the image.
The known optical sensor has the disadvantage that the image rate of the camera is relatively low, so that the system is not suitable for determining a code on a substrate that moves with respect to the camera at high speed. Further, the optical sensor is limited with respect to substrates on which a code can be detected and with respect to ranges of values of the reflective properties within which the sensor may operate. For instance on highly reflective substrates, e.g., comprising a mirror-like surface, the known sensor is unable to detect a code.
It is an object of the invention to at least diminish at least one of the mentioned problems.